1. Field of the Invention
The present invention relates generally to a broadcast service method in a mobile broadcast system and a system thereof, and in particular, to a method and system for protecting broadcast service/content between network entities constituting a broadcast system and a method for generating encryption keys and messages using the same.
2. Description of the Related Art
The mobile communication market constantly incurs the need for new services by combining or integrating the existing technologies. Today, the conventional mobile communication system has been developed to provide broadcast services through portable terminals (or mobile terminals) such as a mobile phone and Personal Digital Assistant (PDA). Convergence of mobile communication service and Internet Protocol (IP) technology is now the mainstream of the next generation mobile communication technology due to market needs, the increasing user demand for multimedia services, the strategy of the service providers for providing new services such as broadcast service in addition to the existing voice service, and the interests of Information Technology (IT) companies that are reinforcing their mobile communication business to meet the user demands.
Open Mobile Alliance (OMA), which is a group for studying the standard for interworking between individual mobile solutions, establishes various application standards for features such as mobile games and Internet service. In particular, OMA Browser And Content (BAC) Mobile Broadcast (BCAST) Sub Working Group, one of the OMA working groups, is studying the technology for providing broadcast services using mobile terminals. A brief description will now be made of a mobile broadcast system being discussed in OMA BCAST Working Group.
FIG. 1 is a block diagram illustrating network architecture of a conventional mobile broadcast system.
Referring to FIG. 1, a Content Creation (CC) 10 is a broadcast service (hereinafter BCAST service) provider, and the BCAST service can include the conventional audio/video broadcast service and file (music or data file) download service. A BCAST Service Application (BSA) 20 generates BCAST service data by processing BCAST service data provided from the CC 10 into the form suitable for the BCAST network of FIG. 1, and also generates standardized metadata necessary for a mobile broadcast guide.
A BCAST Service Distribution/Adaptation (BSD/A) 30 sets up a bearer over which it will transmit the BCAST service data provided from the BSA 20, determines transmission schedules of the BCAST services, and generates a mobile broadcast guide. A BCAST Subscription Management (BSM) 40 manages subscription information and BCAST service provisioning information for receipt of the BCAST service, and device information for a mobile terminal receiving the BCAST service.
A Terminal 50 is capable of receiving the BCAST service, and has a function capable of connecting with a cellular network according to terminal capability. Herein, the Terminal 50 is assumed to be connectable with the cellular network. A Broadcast Network 60 is for transmitting the BCAST service, and can be for Digital Video Broadcasting-Handheld (DVB-H), 3GPP Multimedia Broadcast and Multicast Services (MBMS) and 3GPP2 Broadcast and Multicast Services (BCMCS), for example. An Interaction Network 70 is for transmitting the BCAST service on a point-to-point basis, or interactively exchanging control information and additional information related to the receipt of the BCAST service, and can be, for example, the existing cellular network.
In BCAST service, a plurality of mobile terminals receive encrypted service data transmitted by a server for managing broadcast services. The mobile terminals can use the corresponding service by deciphering the encrypted service data provided from the server using an encryption key previous stored therein. In this context, a method for encrypting broadcast content/service is roughly divided into service protection and content protection. Service protection indicates protection of a transmission channel between the BCAST Service Distribution/Adaptation (BSD/A) 30 and the Terminal 50, and content protection indicates end-to-end protection between the BSA 20 and the Terminal 50.
However, in the current mobile broadcast system, there is no detailed proposed scheme such as a method and procedure for generating and transmitting encryption keys and messages for encryption of broadcast service and/or content between the entities constituting a broadcast system, for the safe transmission of broadcast service and/or content. Therefore, a need exists for introduction of such a scheme.